Dong Hyun Chun

Highly activated K-doped iron carbide nanocatalysts designed by computational simulation for Fischer–Tropsch synthesis

Although the reaction results of numerous iron-based Fischer–Tropsch synthesis catalysts containing various promoters have been reported, the research on their theoretical foundation is still insufficient. In the present work, highly activated K-doped χ-Fe5C2/charcoal nanocatalysts were designed using calculations based on density functional theory (DFT), and then prepared using a melt-infiltration process and a subsequent incipient-wetness method of K precursors. The catalyst at K/Fe = 0.075 in an atomic ratio that bears small iron carbide nanoparticles of ∼18 nm showed the highest activity (1.54 × 10−4 molCO gFe−1 s−1) and the best hydrocarbon yield (1.41 × 10−3 gHC gFe−1 s−1), as well as a good selectivity for gasoline-range (C5–C12) hydrocarbon products in the high-temperature Fischer–Tropsch reaction.

Cs promoted Fe5C2/charcoal nanocatalysts for sustainable liquid fuel production

Cs promoted Fe5C2/charcoal nanocatalysts bearing small iron carbide particles of 8.5 and 14 nm were prepared through a simple melt-infiltration process and a wetness impregnation method; the resulting materials showed very high CO conversion (>95%) and good selectivity, especially at Cs/Fe = 0.025, resulting in a high liquid oil productivity (∼0.4 gliq gcat−1 h−1) in high-temperature Fischer–Tropsch synthesis.

Effects of SiO 2 Incorporation Sequence on the Catalytic Properties of Iron-Based Fischer-Tropsch Catalysts Containing Residual Sodium

Fischer–Tropsch synthesis was carried out over industrially important Fe/Cu/K/SiO2 catalysts containing a small amount of residual sodium which originated from the sodium carbonate solution used as a precipitating agent. The structural promoter, SiO2, was incorporated by two comparative sequences: immediately after precipitation (AP) or after a subsequent wash (AW). Whereas AW exhibited severe deactivation during the reaction, AP displayed high and stable catalytic activity for the entire reaction time. Furthermore, AP showed higher selectivity of liquid hydrocarbons, in particular heavy hydrocarbons, than AW. We attribute the advantageous catalytic performance observed in AP to the enhanced reducibility and higher surface basicity of AP, potentially induced by higher dispersion of catalysts and promoters.Graphical Abstract

Robust iron-carbide nanoparticles supported on alumina for sustainable production of gasoline-range hydrocarbons

The high-temperature Fischer–Tropsch synthesis reaction has been exploited to selectively produce lower-olefins and gasoline-range hydrocarbons (C5–C12) from a mixture of carbon monoxide and hydrogen, using iron-based catalysts. For this reaction, improving the selectivity and stability of the catalyst has been a major challenge, as has enhancing the activity. In the present work, we introduce iron-carbide nanoparticles supported on a porous gamma-alumina framework as a robust catalyst, prepared via a simple melt infiltration process and subsequent thermal treatment, for high-temperature Fischer–Tropsch synthesis. The iron-carbide/alumina catalyst showed much better catalytic performance, with a higher stability for producing gasoline-range hydrocarbon products, than did iron-carbide/mesoporous silica (SBA-15) and iron-carbide/activated carbon (AC).

Large-scale synthesis of uniformly loaded cobalt nanoparticles on alumina for efficient clean fuel production

Large-scale synthesis of cobalt nanoparticles supported on alumina (Co/Al2O3), which has well dispersed metallic cobalt around 15 nm, was conducted via a simple melt infiltration process of a cobalt hydrate salt and subsequent thermal reduction. The catalytic performance of Co/Al2O3 was studied for Fischer–Tropsch synthesis in order to optimize the liquid fuel productivity for target hydrocarbon products controlled by reaction pressures and temperatures. The catalyst showed promising CO conversions up to 76% with high hydrocarbon productivity (∼1.0 gHC gcat−1 h−1) and good stability.

Synthesis of Co/SiO2 hybrid nanocatalyst via twisted Co3Si2O5(OH)4 nanosheets for high-temperature Fischer–Tropsch reaction

A cobalt-silica hybrid nanocatalyst bearing small cobalt particles of diameter ~5 nm was prepared through a hydrothermal reaction and hydrogen reduction. The resulting material showed very high CO conversion (>82%) and high hydrocarbon productivity (~1.0 gHC·g−1cat·h−1) with high activity (~8.5 × 10−5 molCO·gCo−1·s−1) in the Fischer–Tropsch synthesis reaction.

Highly productive cobalt nanoparticles supported on mesocellular silica foam for the Fischer–Tropsch reaction

We prepared highly productive Co/MCF nanocatalysts by a facile melt infiltration process using a hydrated Co precursor. The highly loaded Co particles (30 wt%) were uniformly dispersed in the large pores (30 nm) of the MCF support. The Co particles had an average diameter of 17 nm and clean surfaces without any surfactant. The Co/MCF catalyst exhibited very high hydrocarbon productivity (∼0.98 gtotal HC gcat−1 h−1) with high activity (CO conversion = 77%, CTY = 7.6 × 10−5 molCO gCo−1 s−1) and good selectivity for C5+ long chain hydrocarbons (∼81%) in Fischer–Tropsch synthesis.

Hyperactive iron carbide@N-doped reduced graphene oxide/carbon nanotube hybrid architecture for rapid CO hydrogenation

A hierarchical architecture designated as Fe5C2@Ns-rGO/CNT, consisting of carbon nanotubes, steam activated N-doped reduced graphene oxides, and activated iron carbide nanoparticles, was prepared via microwave irradiation and subsequent CO activation. The Fe5C2@Ns-rGO/CNT was successfully applied to a rapid CO hydrogenation reaction showing extremely high activity of 4.4 × 10−3 molCO gFe−1 s−1 at a fast gas velocity of 210 NL gcat−1 h−1.